Soldering flux



Patented Sept. '7, 1937 Charles A. Thomas, Dayton, Ohio, assignmto Standard Cap and Seal Corporation, New York, N. Y., a corporation of Virginia He Drawing. Application May 21, 1932, Serial No. 612,870. Renewed January 28, 1937 1 fl'ilaim. (Cl. 148-25) This invention relates to a process of soldering and a composition adapted to be used as a soldering flux.

One of the principal objects of this invention is to provide a process whereby metallic surfaces,

such as tinned steel wire may be readily cemented together by the application of heat, the eflec'tiveness of such soldering process being unaffected by exposure of the metallic surfaces to air' for relatively long periods of time.

Another object is to provide a composition which acts as a flux'in the cementing or soldering of such metallic surfaces, such fluxing composition being unaffected by exposure to air.

'15 Other objects andadvantages of the invention will be apparent from the following description and appended claim.

In cementing together metallic surfaces such as steel wire, a soldering process is generally 20 utilized. This may be done by first passing steel wire through a bath of molten solder, and later cementing together the resulting tinned surfaces by the application of heat; The solder thus acts.

- as a seal to fasten together the metallic surfaces 26 in the desired position, for example, overlapping ends of a wire may be mechanically held in position during the applicationv of heat and until sufliciently cooled and hardened so that the solder holds together the ends in the desired posi- 30 tion. This type of seal is especially applicable to wire closures for hood-type bottle caps, such as used on milk bottles and the like. when the timed coating or surface is fresh, cohesion between such surfaces is readily obtained by the 85 simple application 'of the required degree of heat.

' However, if allowed to stand exposed to air until oxidation has taken place it is found that use of a fluxing agent is necessary to obtain cohesion between the surfaces- It is found that oils, such 40 as lard oil, which have heretofore been suggested for this purpose, are readily oxidized on standing exposed to the air, and become rancid and so changed-in character and properties that they no longer act as a flux in the soldering'operation.

Consequently, wires with such materials and then allowed to stand exposed to air until oxidation takes place, cannot be effectively soldered by heat alone without further treatment.

. It is'desirable that the mixing-material used be 50 capable of application by a simple treatment in such manner the no excess is present, and that it be of such character as not to be affected by exposuretoain.

able soldering material, and is then coated with a solution of a soluble fluxing agent in a stable oil which is non-oxidizable by exposure to air, such as paraiiin oil, such wire may be exposed to air without danger of oxidization or deterioration 5 of the coating film. The non-oxidizing oil is thus used as a solvent and. carrier for the fiuxing agent. A tin coating of this fluxing composition acts as a fluxing agent when heat is applied to the tinned surfaces, and satisfactory cohesion 10 between the tinned surfaces Iis readily obtained regardless of'prolonged exposure to air. It is also found that further addition of fluxing agent or other treatment during or preceding the soldering operation is unnecessary.

As an example of the carrying out of this invention thefreshly tinned wire is passed through a bath comprising paraffin-oil containing in solution approximately 5 per cent by weight of a solu- 1 ble fiuxing agent, suchas pine rosin, carnauba wax, ha'lowax or halowax oil (chlorinated naphthalenes) The composition forms on the wire a thin coating which is not affected by exposure to air. when it is desired to cement together any surfaces of the coated wire, esfor example, overlapping ends, the parts to be cemented are clamped or held in the desired position, and heat is then applied in any desired manner as by passing an electric current through the wire. The tin or solder coating on the wire in conjunction so with the fluxing agent coated thereon readily fluxes on the application of heat, and on being allowed to cool it hardens in position. A tight seal between the ends of the wire is thus obtained.

Any stable oil which is not affected by exposure as to ahead .which' is capable of forming a nonvolatile fllm on the surface to be soldered, may be used as a solvent or carrier,-according to the invention, such for example as asphalt base oils such as paramn oil, light lubricating oils and the 40 like. Any-fluxing agent which is readily soluble in the solvent oil used and which is not oxidized, decomposed or rancidifled by exposure to air, may be satisfactorily used to form a .fluxingcomposition according to. this invention. For example, halowax, halowax-oil, pine rosin and carnauba wax have been found to give good results. The proportions of fluxing agent used may vary widely but in general it has been found that a non-oxidizing oil, is suillcient to give a-satisfactory fluxing action.

In some cases considerably less may be used, for example, a composition containing approximately 2% per cent by weight 553 of carnauba wax and 97% per cent of parefin oil has been found satisfactory.

While the methods herein described and the products so produced constitute preferred embodiments of this invention, it is to be understood that the invention is not limited to these precise methods or precise products,v and that changes may be made therein without departing from the scope of the invention which is described in the i0 appended claim. I

What is claimed is:

A lirguid soldering flux consisting of a non=cor= rosive rosin fiuxing agent in solution in a. stable, non-oxidizing lubricating oil, the solution being in the proportion of approximately 5 per cent by weight of fiumng agent and apprommately 95 per cent by weight of oil capable of forming on a.

solder coated metallic wire, a combined fluxing and protective film for the purpose set forth.

omm-ns A. "moms. 10 

